unity3相机跟随物体移动

1.向量转四元数
Quaternion.LookRotation(dir);—>返回值就是一个四元数
2.开始旋转
transform.rotation = Quaternion.Lerp(当前的四元数, 目标四元数, 旋转的速度);
3.普通相机跟随

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CameraMovement : MonoBehaviour {
///
/// 跟随目标
///
public Transform followTarget;
///
/// 方向向量
///
private Vector3 dir;

private void Start()
{
    //获取方向向量
    dir = transform.position - followTarget.position;
}

private void Update()
{
    transform.position = dir + followTarget.position;
}

}
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CameraMovement : MonoBehaviour {
///
/// 跟随目标
///
public Transform followTarget;
///
/// 方向向量
///
private Vector3 dir;

private void Start()
{
    //获取方向向量
    dir = transform.position - followTarget.position;
}

private void Update()
{
    transform.position = dir + followTarget.position;
}

}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CameraMovement : MonoBehaviour {

/// <summary>
/// 俯视距离的偏移量
/// </summary>
public float offset = 0.5f;
/// <summary>
/// 设置中间的相机位置个数
/// </summary>
public int gears = 5;
/// <summary>
/// 跟随目标
/// </summary>
public Transform followTarget;
/// <summary>
/// 方向向量
/// </summary>
private Vector3 dir;
/// <summary>
/// 待选的相机位置(观察点)
/// </summary>
private Vector3[] readyPosition;
/// <summary>
/// 射线碰撞检测器
/// </summary>
private RaycastHit hit;
/// <summary>
/// 相机跟随的移动速度
/// </summary>
public int moveSpeed = 1;
/// <summary>
/// 相机旋转的速度
/// </summary>
public float turnSpeed = 10f;
private void Start()
{
    //获取方向向量
    dir = transform.position - followTarget.position;
    //实例化观察点数组
    readyPosition = new Vector3[gears];

}

private void Update()
{
    //相机的起点--->相机最佳视角
    Vector3 begin = dir + followTarget.position;
    //相机的终点--->相机最差视角保证能看到玩家
    Vector3 end = followTarget.position + Vector3.up * (dir.magnitude - offset);
    //把起点和终点放到观察点的数组中
    readyPosition[0] = begin;
    readyPosition[readyPosition.Length - 1] = end;
    //获取相机中间点的位置
    for (int i = 1; i < readyPosition.Length - 1; i++)
    {
        //求中间点各个点的坐标,比例为i / (gears - 1)
        readyPosition[i] = Vector3.Lerp(begin, end, i / (readyPosition.Length - 1));
    }
    //备选方案--->前面所有的观察点都看不到玩家
    //都看不到就把相机放到最佳视角
    Vector3 watchPoint = begin;
    //遍历观察点数组,挑选我们最佳观察点
    for (int i = 0; i < readyPosition.Length; i++)
    {
        if (CheckWatchPoint(readyPosition[i]))
        {
            //设置观察点
            watchPoint = readyPosition[i];
            //得到观察点退出循环
            break;
        }
    }
    //相机平滑移动到最佳观察点
    transform.position = Vector3.Lerp(transform.position, watchPoint, Time.deltaTime * moveSpeed);
    /*
      //旋转的不是很平滑
      //相机旋转到最佳角度看向玩家
      transform.LookAt(followTarget);
     */
    //获取方向向量
    Vector3 lookDir = followTarget.position - watchPoint;
    //获取四元数
    Quaternion lookQua = Quaternion.LookRotation(lookDir);
    //平滑转向玩家
    transform.rotation = Quaternion.Lerp(transform.rotation, lookQua, Time.deltaTime * turnSpeed);
    //固定相机y轴z轴的旋转
    transform.eulerAngles = new Vector3(transform.eulerAngles.x, 0, 0);

}
/// <summary>
/// 检测观察点是否可以看到目标
/// </summary>
/// <param name="point">待选的观察点</param>
/// <returns><c>true</c>看得到<c>false</c>看不到</returns>
bool CheckWatchPoint(Vector3 point)
{
    if (Physics.Raycast(point,followTarget.position - point,out hit))
    {
        //如果射线检测到的是玩家
        if (hit.collider.tag == "Player")
        {
            return true;
        }
    }

    return false;
}

}
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CameraMovement : MonoBehaviour {

/// <summary>
/// 俯视距离的偏移量
/// </summary>
public float offset = 0.5f;
/// <summary>
/// 设置中间的相机位置个数
/// </summary>
public int gears = 5;
/// <summary>
/// 跟随目标
/// </summary>
public Transform followTarget;
/// <summary>
/// 方向向量
/// </summary>
private Vector3 dir;
/// <summary>
/// 待选的相机位置(观察点)
/// </summary>
private Vector3[] readyPosition;
/// <summary>
/// 射线碰撞检测器
/// </summary>
private RaycastHit hit;
/// <summary>
/// 相机跟随的移动速度
/// </summary>
public int moveSpeed = 1;
/// <summary>
/// 相机旋转的速度
/// </summary>
public float turnSpeed = 10f;
private void Start()
{
    //获取方向向量
    dir = transform.position - followTarget.position;
    //实例化观察点数组
    readyPosition = new Vector3[gears];

}

private void Update()
{
    //相机的起点--->相机最佳视角
    Vector3 begin = dir + followTarget.position;
    //相机的终点--->相机最差视角保证能看到玩家
    Vector3 end = followTarget.position + Vector3.up * (dir.magnitude - offset);
    //把起点和终点放到观察点的数组中
    readyPosition[0] = begin;
    readyPosition[readyPosition.Length - 1] = end;
    //获取相机中间点的位置
    for (int i = 1; i < readyPosition.Length - 1; i++)
    {
        //求中间点各个点的坐标,比例为i / (gears - 1)
        readyPosition[i] = Vector3.Lerp(begin, end, i / (readyPosition.Length - 1));
    }
    //备选方案--->前面所有的观察点都看不到玩家
    //都看不到就把相机放到最佳视角
    Vector3 watchPoint = begin;
    //遍历观察点数组,挑选我们最佳观察点
    for (int i = 0; i < readyPosition.Length; i++)
    {
        if (CheckWatchPoint(readyPosition[i]))
        {
            //设置观察点
            watchPoint = readyPosition[i];
            //得到观察点退出循环
            break;
        }
    }
    //相机平滑移动到最佳观察点
    transform.position = Vector3.Lerp(transform.position, watchPoint, Time.deltaTime * moveSpeed);
    /*
      //旋转的不是很平滑
      //相机旋转到最佳角度看向玩家
      transform.LookAt(followTarget);
     */
    //获取方向向量
    Vector3 lookDir = followTarget.position - watchPoint;
    //获取四元数
    Quaternion lookQua = Quaternion.LookRotation(lookDir);
    //平滑转向玩家
    transform.rotation = Quaternion.Lerp(transform.rotation, lookQua, Time.deltaTime * turnSpeed);
    //固定相机y轴z轴的旋转
    transform.eulerAngles = new Vector3(transform.eulerAngles.x, 0, 0);

}
/// <summary>
/// 检测观察点是否可以看到目标
/// </summary>
/// <param name="point">待选的观察点</param>
/// <returns><c>true</c>看得到<c>false</c>看不到</returns>
bool CheckWatchPoint(Vector3 point)
{
    if (Physics.Raycast(point,followTarget.position - point,out hit))
    {
        //如果射线检测到的是玩家
        if (hit.collider.tag == "Player")
        {
            return true;
        }
    }

    return false;
}

}

相机跟随一直观察角色背部

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CameraFollow : MonoBehaviour {

public Transform target;
public float distanceUp = 5f;
public float distanceAway = 5f;
public float smooth = 2f;//位置平滑移动值
public float camDepthSmooth = 2f;
// Use this for initialization
void Start()
{

}

// Update is called once per frame
void Update()
{
    // 鼠标轴控制相机的远近
    if ((Input.mouseScrollDelta.y < 0 && Camera.main.fieldOfView >= 3) || Input.mouseScrollDelta.y > 0 && Camera.main.fieldOfView <= 80)
    {
        Camera.main.fieldOfView += Input.mouseScrollDelta.y * camDepthSmooth * Time.deltaTime;
    }

}

void LateUpdate()
{
    //相机的位置
    Vector3 disPos = target.position + Vector3.up * distanceUp - target.forward * distanceAway;
    transform.position = Vector3.Lerp(transform.position, disPos, Time.deltaTime * smooth);
    //相机的角度
    transform.LookAt(target.position);
}

}